preauth for Zimbra Admin console?

I've seen examples of using pre-auth to authenticate users and redirect them to a URL that will allow an "autologin". Is it also possible to do a similar thing to automatically log people into the admin console?

Would it work to make a soap call to AuthRequest, get the AuthToken and set that as a presistent cookie (say 1 day into the future) and then re-direct them to to the login URL, which would hopefully see the cookie and let them bypass the login prompt?

Granted, might be re-inventing the wheel a bit, but I'm familiar that calling AuthRequest for getting user information and I'd rather stick with what I've been able to get working in the past.